Do not use a reference to a temporary object. (Caught by some additional warnings that @ellyjones was building with)

PiperOrigin-RevId: 486229659
diff --git a/quiche/spdy/core/spdy_alt_svc_wire_format_test.cc b/quiche/spdy/core/spdy_alt_svc_wire_format_test.cc
index 68f988d..50c67a3 100644
--- a/quiche/spdy/core/spdy_alt_svc_wire_format_test.cc
+++ b/quiche/spdy/core/spdy_alt_svc_wire_format_test.cc
@@ -380,7 +380,7 @@
   SpdyAltSvcWireFormat::AlternativeServiceVector altsvc_vector;
   const char* field_value_array[] = {"a=\":137\"", "a=\"foo:137\"",
                                      "a%25=\"foo\\\"bar\\\\baz:137\""};
-  for (const std::string& field_value : field_value_array) {
+  for (const absl::string_view field_value : field_value_array) {
     for (size_t len = 1; len < field_value.size(); ++len) {
       EXPECT_FALSE(SpdyAltSvcWireFormat::ParseHeaderFieldValue(
           field_value.substr(0, len), &altsvc_vector))